High tension transformer



1 Aug. 23, 1932. c. SCHRADER I HIGH TENSION TRANSFORMER Filed May 4, 1929 J-Mva-Mfoa CARL sCI -(RApA-R fi n-ve.

Patented 1932 IUNIT'EDYSTATES PATENT OFFICE caanscnnaimit, cranium-mamas, GERMANY, ASSIGNOIB 'ro smmms a musxa, 'mmnersnuscmr, or smmmrssrran'r, NEAR BERLIN, GERMANY, a conroaa- TION OF GERMANY anon TENSION Jamar-mm t a lication filed Ian, 1929, Serial No. 360,398, and in. Germany Kay 4, 1923.

My invention relates to improvements in the arrangement of the insulation of transformers, more particularly transformers of the cross-ring type. I

The high-tension insulation of transformers is generally so designed, that apart from the independent insulating members between the primary and the secondary winding the duty of effecting the insulation is almost solely entrusted to the insulating envelope of the winding carrying high voltages itself or to ground, in the case of measuring transformers to the rimary windin as hitherto constructed, t e primary Win 'ng of cross-ring transformers, in particular, is so strongly enclosed in insulating material, that the hole in the core is completely filled up by such primary insulation, while the secondary winding is only insulated against the iron'of the core, so that the insulationnecessary to prevent an arc-over is very unevenl distributed 'between the primary and secon ary coils. 3

According to myinvention, the insulation is distributed substantially uniformly upon the iron core and the high tension winding, so that both are enclosedg-.. by insulating envelopes of substantially the-same dimensions.

There are obtained in this way a number of advantages which will be explained in connection with the accompanyin drawing in which such a transformer of t e cross-ring type is illustrated diagrammatically by way of example. In said drawing:

Fig. *1 shows the transformer in elevation with the enclosing casing in longitudinal section, and

Fig. 2 represents a longitudinal section through the transformer, on a larger scale.

Like partsare indicated by like numerals of reference in both figures of the drawing.

Referring'to the drawing, it will be seen that a hollow ring 1 consisting of a suitable insulating material envelopes the primary winding 2 of the transformer, and a similar a hollow ring 3 envelopes theiron core 4 with the secondary winding 5 wound u on it. 'Iuhular insulating extensions 6 an 7 on these v ring'senvelope the ends 8 and 9 of the windin'gs brought out and connected to the termmals 10 and 11. "The carriers of the iron core 4 are indicated at 16. The secondary winding 5 is enveloped by a metal shell 12 which contacts the same at theedges or corners, and which eliminates the detrimental effect of the edges of the winding by preventing the accumulation of electrostatic charges thereon. The primary winding is in a similar manner protected bya shell 12.

As can be seen from the drawing, the arcover distance is'increased as compared with a transformer having insulation arranged entirely upon the high tension winding. As, further, the voltage distribution depends upon the magnitude of the capacity between the windings, the iron core and the housing of the transformer, the field distribution in the arc-over gap can be controlled by altering the position of the high tension winding, the iron core, or the oil container relatively to each other. It is therefore possible to determine the position for all the parts in which the field distribution is most favorable and consequently the arc-over distance can become the mostfavorable for a given tension. Finally, the field distribution can be controlled by suitable distribution of the insulation upon the parts, to be insulated. If necessary the extensions 6 and 7 are made of difierent len hs.

By relieving t e primary winding of part of its insulating layer its heat dissipation is at the same time increased. The quantity of the dielectric material is also reduced by distributing it over two rings on account of the smaller radius of the cross-section. In order to prevent disturbances of the field by surrounding masses of metal, the casing 13 is preferably constructed of a dielectric ma-' terial, such as a. ceramic 'material, either partly or completely. If the transformer is filled with oil, the closure of the casing is preferably effected by a cemented ceramic plate 14, in order to avoid the inconveniences arising from cementing together ceramic materials and metal. The metal fitting is then placed on this ceramic plate 14. This method of sealing the casing is not only of advantage for the cross-ring transformer illustrated by way of example, but generally for oil-filled transformer casings constructed of non-metallic materials.

Various modifications and changes may be made without departing from the spirit and the scope of the invention, and I desire, there-.

fore, that only such limitations shall be placed thereon as are imposed by the prior art.

-I claim as my invention:

1. In a transformer, in combination, an

iron core of substantially annular form about which the secondary winding of the transformer is wound, a substantially annular high tension winding passing through said iron core perpendicularly to the plane thereof, and envelopes for said iron core and the high tension winding completely surrounding the same, said envelopes being made of insulating material of substantially equal dimensions, and adapted together to insulate the transformer against the maximum tension thereof.

2. In a transformer, in combination, an

iron core of substantially annular form about which the low tension winding of the transformer housing, and adapted together to insulate the transformer against the maximum tension thereof.

3. In a transformer, in combination, an iron core of substantially annular form about which the low tension winding of the transformer is wound, a substantially annular high tension winding, said high tension winding passing through said iron core perpendicularly to the plane thereof, insulating envelopes for the iron core and the high tension winding of substantially equal dimensions and completely surrounding the same, and a housing of insulating material for receiving said core, windings and insulating envelopes, said envelopes adapted together to insulate the transformer against the maximum tension thereof.

4, In a transformer, in combination, an iron core of substantially annular form about which the low tension winding of the transformer is wound, a substantially annular high tension winding, said high tension.

winding passing through said iron core perpendicularly to the plane thereof, insulating envelopes for the iron core and the high tension winding of substantially equal dimensions and completely surrounding the same, low tension and high tension terminal coriductors extending in opposite directions from points on the iron core and on the high ten,

sion winding as far removed' as possiblefrom each other, said insulating envelopes being enlarged over at least a part .of the current conductors leading. to said windings and being adapted together to insulate the transformer against the maximum tension thereof, and a casing of insulating material for said transformer. I

5. In a transformer, in combination, an

iron core of substantially annular form about envelopes for the iron coreand the high ten-.

sion winding of substantially equal dimensions and completely surrounding the same, a housing of insulating material for said transformer, and closure plates likewise of insulating material adapted to be attached to said housing, said envelopes adapted together to insulate the transformer against the maximum tension thereof.

6. In a transformer, in combination, an iron core of substantially annular form about which the low tension winding of the transformer is wound, a substantially' annular high tension winding, said high tension winding passing through said iron core perpendicularly to the plane thereof, insulating envelopes for the iron core and the high tension winding of substantially equal dimensions and completely surrounding the same, low tension and high tension terminal conductors extending in opposite directions from points on the iron 'core and on the high tension winding as far removed as possible from each other, said insulating envelopes being enlarged over at least a part of the current conductors leading to the windings and being adapted together to insulate the transformer against the maximum tension thereof, a housing of insulating material for said transformer, and closure plates like wise of insulating material adapted to be attached to said housing.

7. In a transformer, in combination, an

iron-core of substantially annular form about.

which the low tension winding of the transformer is wound. a substantially annular high tension winding, said high tension winding passing through said iron core perpendicularly to the plane thereof, insulating envelopes for the iron core and the hi h tension winding of substantially equal mensions and completel surrounding the same, a housing of insu ating material for the transformer, closure plates of insulatin material adapted to be cemented to said ouse ing and metallic cap plates for protecting the points of connection between said first men- I tioned plates and the housing, said envelopes adapted together to insulate the transformer against the maximum tension thereof. 8. In a transformer, in combination, an iron core of substantially annular form about which the low tension winding of the transformer is wound, a substantially annular high tension winding, said high tension winding passing through said iron core perpendioularly to the plane thereof, insulatin envelopes for the iron core and the big tension winding of substantially equal di- -mensions and completely surrounding the same, low tension and high tension terminal conductors extending in opposite directions from points on the iron core and on the high tension winding as far-removed as possible from each other, said insulating envelopes being enlarged over at least a part of the current conductors leading to the winding and adapted together to insulate the transformer against the maximum tension thereof, a housing of insulating material for the transformer, closure plates likewise of-insulating material adapted to be cemented to the housing, and metallic cap plates for protecting the points of connection between the first mentioned plates and the container.-

' so In testimony whereof I aifix my signature.

-. CARL SCHRADER. 

